You should be fine, even with a 7.5' Fisher, which is a heavy plow. I think you'd want the 7.5' to clear that wheelbase. You could also call plow dealers in your area for Tahoe application. You could also look into a set of load boosters - there are several on the market at relatively small cost.
Joel; your Tahoe will do just fine with a 7'6 "standard duty" plow. Most "poly" moldboard plows will add extra weight, so take this into consideration when you make your choice. Both Timbren and Monroe make an excellent set of load boosters for the front of your truck.
JOEL, like i posted before...i had a 94 yukon and had a
7 1/2 western on it..with NO problems plowing my
businesses. Truck was dead bone stock too and
turned on a dime. Wanted another but needed a